1. Field of the Invention
The present invention relates to a solar cell material. More particularly, the present invention relates to a photosensitizer dye applicable in dye-sensitized solar cells (DSCs).
2. Description of Related Art
Not only the supply of fossil fuels is expected to run out in an imminent future, the high consumption of fossil fuels also poses an alarming threat to the environment and public health due to their poisonous emissions. Accordingly, scientists are constantly in searching and developing the renewable and sustainable energy sources. The renewable energy sources include: solar energy, wind energy, hydraulic energy, tidal energy, geothermal energy, biomass energy, and etc. Amongst the various types of energy sources, solar energy has been one of the most pursued due to its abundant supply. Furthermore, the application of solar energy is not limited by the physical environment or geomorphology, and solar energy can be directly converted to electricity with the appropriate devices which are known as solar cells (or photovoltaic cells).
Recently, Grätzel and O'Regan have proposed a new type of solar cell known as dye-sensitized solar cells (DSCs). DSCs offer many advantageous prospects, such as, high photoelectric conversion efficiency, high transparency, colorfulness, and flexibility in which the cell is capable of folding or bending. Hence, the dye-sensitized solar cells are well received in the industry. A dye-sensitized solar cell is typically constituted with four parts including an anode/cathode for current flow, a semiconductor material (such as, titanium dioxide (TiO2) or zinc oxide (ZnO)) for accepting and transporting electrons, a monolayer of photossensitizer (dye) attached onto the surface of the semiconductor material in a self-assembly manner, and an electrolyte for transporting holes. The materials used at each part and the interface between each part in the dye-sensitized solar cell play important roles on the photoelectrical conversion efficiency of the cell. Most particularly, the dye used in the photosensitizer layer is the most critical in determining the efficiency of a dye-sensitized solar cell.
Accordingly, to identify a dye that has a high absorption coefficient for enhancing the photoelectrical conversion efficiency of a dye-sensitized solar cell has been enthusiastically pursued in the dye-sensitized solar cell community.